Damped float response on an agricultural harvester

Abstract

A header assembly for an agricultural harvesting machine having a traction unit comprises a cutter, a main frame that supports the cutter, a float cylinder configured to be coupled between the main frame and the traction unit, an accumulator, and fluidic circuitry that fluidically couples the accumulator to the float cylinder. The fluidic circuitry is configured to provide a first flow of pressurized fluid under pressure to the float cylinder, so the float cylinder exerts a float force on the main frame, and, based on a control input that corresponds to a lifting operation of the header assembly, provide a restricted flow of fluid, that is restricted relative to the first flow, between the float cylinder and the accumulator.

What is claimed is: 
     
       1. A header assembly for an agricultural harvesting machine having a traction unit, the header assembly comprising:
 a cutter; 
 a main frame that supports the cutter; 
 a float cylinder; 
 an accumulator; and 
 fluidic circuitry that fluidically couples the accumulator to the float cylinder and includes
 a flow restricting feature, the fluidic circuitry having 
 a first configuration in which a first flow of pressurized fluid under pressure to the float cylinder exerts a float force on the main frame relative to the traction unit; and 
 a second configuration corresponding to a lifting operation in which the main frame is lifted relative to the traction unit, wherein, when in the second configuration, the flow restricting feature restricts a second flow of fluid from the float cylinder to the accumulator. 
 
 
     
     
       2. The header assembly of  claim 1 , wherein
 the fluidic circuitry comprises:
 a first fluid conduit, and 
 a valve mechanism that is actuatable, based on the control input, between a first position and a second position, 
 
 the first position of the valve mechanism permits the first flow through the first fluid conduit, and 
 the second position inhibits flow through the first fluid conduit and provides the second flow of fluid through the flow restricting feature. 
 
     
     
       3. The header assembly of  claim 2 , wherein the fluidic circuitry comprises:
 a second fluid conduit disposed in parallel with the first fluid conduit and having the flow restricting feature configured to provide the restricted flow between the float cylinder and the accumulator when the valve mechanism is in the second position. 
 
     
     
       4. The header assembly of  claim 3 , wherein the flow restricting feature comprises a flow restricting orifice in the second fluid conduit between the float cylinder and the accumulator. 
     
     
       5. The header assembly of  claim 4 , wherein the flow restricting orifice defines an orifice opening that is smaller than the first fluid conduit. 
     
     
       6. The header assembly of  claim 5 , wherein the flow restricting orifice comprises:
 a fixed orifice that has a fixed size orifice opening. 
 
     
     
       7. The header assembly of  claim 5 , and further comprising:
 a control system configured to operate the fluidic circuitry in the first configuration that provides the first flow of pressurized fluid under pressure, and in the second configuration that provides the restricted flow of fluid. 
 
     
     
       8. The header assembly of  claim 7 , wherein the control input is generated based on an operator input. 
     
     
       9. The header assembly of  claim 7 , wherein the control input is generated based on a sensed direction of movement of the header assembly. 
     
     
       10. The header assembly of  claim 1 , wherein the lifting operation lifts the header assembly off the ground. 
     
     
       11. The header assembly of  claim 1 , and further comprising:
 an attachment frame movably coupled to the main frame, wherein the attachment frame is coupled to the traction unit and the float cylinder exerts a float force on the main frame relative to the attachment frame. 
 
     
     
       12. A float force assembly for a harvesting machine header that is attached to a harvesting machine traction unit, the float force assembly comprising:
 an accumulator; and 
 fluidic circuitry that fluidically couples the accumulator to a float cylinder coupled between the harvesting machine traction unit and the harvesting machine header, wherein the fluidic circuitry comprises a flow restricting feature and a valve mechanism that is actuatable between a first position and a second position,
 wherein
 when the valve mechanism is in the first position, the fluidic circuitry provides a first flow of pressurized fluid under pressure to the float cylinder, so the float cylinder exerts a float force on the main frame; and 
 when the valve mechanism is in the second position, the flow restricting feature provides a restricted flow of fluid, that is restricted relative to the first flow, from the float cylinder to the accumulator. 
 
 
 
     
     
       13. The float force assembly of  claim 12 , wherein the fluidic circuitry comprises:
 a first fluid conduit that is controlled by the valve mechanism; and 
 a second fluid conduit disposed in parallel with the first fluid conduit and having a flow restricting feature configured to provide the restricted flow between the float cylinder and the accumulator when the valve mechanism is in the second position. 
 
     
     
       14. The float force assembly of  claim 13 , wherein the flow restricting feature comprises a flow restricting orifice in the second fluid conduit between the float cylinder and the accumulator, the flow restricting orifice defining an orifice opening that is smaller than the first fluid conduit. 
     
     
       15. The float force assembly of  claim 12 , wherein the valve mechanism is actuated, based on a control input, between the first position and the second position during a lifting operation that lifts the harvesting machine header. 
     
     
       16. The float force assembly of  claim 15 , and further comprising:
 a control system configured to operate the fluidic circuitry in a first mode that provides the first flow of pressurized fluid under pressure, and in a second mode that provides the restricted flow of fluid. 
 
     
     
       17. The float force assembly of  claim 16 , wherein the control input is generated based on an operator input. 
     
     
       18. The float force assembly of  claim 16 , wherein the control input is generated based on a sensed direction of movement of the header assembly. 
     
     
       19. The header assembly of  claim 12 , and further comprising:
 an attachment frame movably coupled to the main frame, wherein the attachment frame is coupled to the traction unit and the float cylinder exerts a float force on the main frame relative to the attachment frame. 
 
     
     
       20. A header for a traction unit of a harvesting machine, the header comprising:
 a cutter; 
 an attachment frame configured to couple the header to the traction unit; 
 a main frame that supports the cutter and is movably coupled to the attachment frame; 
 a float cylinder; 
 an accumulator that is fluidically coupled to the float cylinder through a first fluid conduit that provides a first flow of pressurized fluid under pressure to the float cylinder, so the float cylinder exerts a float force on the main frame relative to the attachment frame; 
 a valve mechanism that is actuatable between a first position that permits the first flow through the first fluid conduit and a second position that inhibits flow through the first fluid conduit; and 
 a second fluid conduit disposed in parallel with the first fluid conduit and having a flow restricting feature configured to provide the restricted flow between the float cylinder and the accumulator when the valve mechanism is in the second position.